Kautilya's Arthashastra 1.9.9

1.9.9

purohitam uditoditakulaśīlaṃ sa-aṅge vede daive nimitte daṇḍanītyāṃ cābhivinītam āpadāṃ daivamānuṣīṇām atharvabhir upāyaiś ca pratikartāraṃ kurvīta //

Him whose family and character are highly spoken of, who is well educated in the Vedás and the six Angas, is skillful in reading portents providential or accidental, is well versed in the science of government, and who is obedient and who can prevent calamities providential or human by performing such expiatory rites as are prescribed in the Atharvaveda, the king shall employ as high priest. As a student his teacher, a son his father, and a servant his master, the king shall follow him.